BK Virus in Salivary Gland Disease: Treating the Potential Etiologic Agent: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for BK Virus in Salivary Gland Disease: Treating the Potential Etiologic Agent (NCT02068846), a randomized phase 3 study. The primary outcome is BK Viral Status in Saliva at Week 4.

2. Clinical Question

The study’s stated purpose was to examine BK viral infection in salivary gland disease and determine whether there is a relationship between BK virus and HIV-associated salivary gland disease. The primary outcome definition focuses on viral status in oral fluid, assessed as positive or negative by real-time PCR. The registry description says the test was intended to assess whether ciprofloxacin administration inhibits BK virus replication.

The study summary also describes an intended relationship between salivary function or protein secretion and BK polyomavirus titers. Secondary outcomes include unstimulated salivary flow rate and participant reports of dry mouth at Week 4 and Week 12. Those measures add clinical context to the viral-status question, but the registry record does not report results for them. It also does not report a primary comparison of the Week 4 viral-status counts.

3. Trial Design

The registry lists this study as Phase 3, randomized, triple-masked, and parallel-group. Participants were assigned to ciprofloxacin or placebo, with the study summary describing a 1:1 allocation. Both treatments were taken twice daily for 28 days. The sponsor was the University of North Carolina, Chapel Hill, and the study status is recorded as completed.

The registry reports enrollment of 17 participants. The primary-outcome description notes that two participants withdrew before Week 4. The safety record lists 9 participants at risk in the ciprofloxacin group and 8 in the placebo group. Those safety denominators describe the participants included in the adverse-event entries; they should not be treated as the unreported primary-outcome counts.

The design compares two parallel groups rather than comparing each participant’s outcome under both treatments. Random assignment is intended, in general, to support a fair comparison by distributing participant characteristics without choosing groups based on expected outcomes. Masking is intended, in general, to reduce the influence of treatment knowledge on participant experience, care, outcome assessment, or other study processes. The registry identifies triple masking but does not state which specific people or roles were masked.

The record does not report the detailed randomization method, allocation concealment procedures, eligibility criteria beyond the summary description of adults with HIV and salivary gland disease, or the precise composition of the analysis populations. It also does not report a sample-size justification or detailed statistical analysis plan. These omissions limit how fully the intended safeguards and analytic decisions can be evaluated from the registry record alone.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Two participants withdrew prior to Week 4

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as BK Viral Status in Saliva at Week 4, measured over Week 4.

The primary endpoint is BK viral status in saliva at Week 4. Oral fluids were to be assessed for evidence of BK virus replication using real-time PCR, with each result classified as positive or negative. The registry describes the endpoint unit as participants and the measure as a count of participants.

A binary viral-status outcome can make a biological question more directly interpretable: it records whether the assay found evidence of BK virus in a participant’s oral fluid at the specified time. The endpoint is relevant to the stated study question because the study aimed to assess BK virus in salivary gland disease and whether ciprofloxacin administration inhibits viral replication. This does not by itself establish a change in salivary function, symptoms, or any other clinical outcome.

For a comparison between randomized groups, the counts or proportions of participants classified as positive and negative would need to be reported for each group, along with an appropriate estimate of the difference and its uncertainty. The registry record defines the endpoint but does not report those group-specific results, an effect estimate, or a confidence interval. The outcome description notes that two participants withdrew before Week 4, but does not state how their missing status results were handled in an analysis.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods are useful only when their inputs and assumptions are clear. In this study, the registry defines a binary primary outcome, describes randomized parallel groups, and reports that two participants withdrew before Week 4. It does not report a primary-outcome analysis. The following concepts explain how such an analysis is generally understood; they are not a description of analyses confirmed to have been performed for this trial.

What does a binary endpoint capture?

A binary endpoint assigns each assessed participant to one of two categories. Here, the categories are BK virus positive and BK virus negative in oral fluid at Week 4. Counts in these categories can be compared across randomized groups. A count alone does not communicate the full comparison unless the relevant group denominator and the treatment contrast are also clear. For example, an outcome count should be interpreted in relation to how many participants in that group had an outcome assessment.

In general, analysts may express a binary-outcome contrast using a difference in proportions, a relative measure, or a model-based estimate. Each form answers the comparison on a different scale. The registry record does not report which measure, if any, was used for the primary comparison, or the group-specific positive and negative counts. No effect measure can therefore be interpreted from the posted primary results.

Why does randomization matter?

In general, random assignment is intended to make treatment groups comparable in expectation, including with respect to characteristics that may affect an outcome. This supports attributing a group contrast to assigned treatment more credibly than a comparison based on self-selected treatment. It does not guarantee identical groups in a particular trial, especially when enrollment is limited. The registry identifies the study as randomized, but does not describe the sequence-generation or allocation-concealment procedures.

A parallel-group design means the assigned groups are followed as distinct groups. Masking can reduce the risk that knowledge of assignment affects participant behavior, co-interventions, outcome assessment, or reporting. The record labels the study triple-masked, but it does not specify the masked roles or describe how masking was maintained.

What would uncertainty add?

An effect estimate gives the observed group contrast, while a confidence interval indicates its statistical uncertainty under the specified model and assumptions. In general, the interval is more informative than a point estimate alone because it conveys the range of contrasts compatible with the analysis. A p-value, if reported, would address compatibility of the data with a specified null hypothesis under an analysis model; it would not give the probability that the null hypothesis is true or measure clinical importance. The registry record reports no primary effect estimate, confidence interval, or p-value.

Why can missing outcomes affect inference?

The primary-outcome description says two participants withdrew before Week 4. In general, an outcome that is not measured cannot simply be assumed to be positive, negative, or unchanged. How missing results are handled can affect the analyzed group counts and the interpretation of a treatment contrast. A complete-case analysis uses participants with observed outcomes; other approaches may use assumptions or models for missingness. These are general options, not methods that can be attributed to this study. The registry record does not report the missing-data method or an analysis population.

What role does dispersion play?

For a binary endpoint, variability is linked to the frequency of each category and to the number of participants assessed. In general, uncertainty increases when there is limited information about the outcome distribution. The registry’s primary endpoint is recorded as a count, with no dispersion measure reported. Without the observed group counts and an analysis, the degree of uncertainty cannot be assessed.

How should planning calculations be read?

In general, sample-size calculations are planning illustrations that depend on a chosen effect size, significance level, allocation, and statistical method. The registry’s stated planning assumptions refer to a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the effect to detect defined as a fraction of the observed effect. Such calculations are not observed power and do not show that a treatment effect was present. The record does not report the primary effect estimate needed to interpret planning quantities based on fractions of that effect. The registry record also does not report the trial’s own sample-size justification.

These methods concepts clarify what would be needed for an interpretable analysis: group-specific endpoint results, a stated comparison measure, uncertainty estimates, and information about missing outcomes and the analysis population. Those details are not reported for the primary endpoint in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists secondary outcomes at Week 4 and Week 12: unstimulated salivary flow rate and participant reports of dry mouth, recorded as Yes/No. Considering several outcomes and time points creates a multiplicity issue in general: the more comparisons an analysis makes, the greater the chance that at least one result appears noteworthy by chance if no adjustment or prioritization is used. A prespecified hierarchy, adjustment procedure, or clear distinction between primary and exploratory analyses can help readers interpret multiple results.

The registry record does not report a multiplicity adjustment, a testing hierarchy, or an analysis plan specifying how these outcomes were to be interpreted together. It also does not report results for the listed secondary outcomes. The primary outcome is defined as BK viral status in saliva at Week 4, but no primary group comparison is reported. The registry’s analysis information does not provide a single comparison that can be assessed from the posted results.

The record notes that two participants withdrew before Week 4. It does not report whether their primary outcome status was unavailable, whether any other outcome data were missing, or how missingness was handled. It also does not state whether the analysis followed assignment regardless of treatment received, included only participants who completed treatment, or used another population definition. These details matter because exclusions or assumptions about missing outcomes can change the composition of the analyzed groups and the conclusions drawn from a comparison.

In general, an intention-to-treat analysis preserves participants in their randomized groups, while other analysis populations may be defined by treatment exposure, adherence, or availability of outcome data. These terms describe general approaches; the registry record does not identify which approach was used. Without an analysis population and missing-data method, it is not possible to assess how the withdrawals were incorporated into the primary analysis.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The safety record lists zero serious adverse events among 9 participants at risk in the ciprofloxacin group and zero among 8 participants at risk in the placebo group. It lists one other adverse event among 9 participants at risk in the ciprofloxacin group and zero among 8 at risk in the placebo group. The record reports zero deaths in both groups.

These are descriptive counts, not estimates of comparative risk. In general, a zero count means that no event of that recorded category appears in the reported group data; it does not demonstrate that the underlying risk is zero. A single recorded event also provides limited information about how often similar events might occur in a broader population. The registry record does not provide event descriptions for the other adverse event, an inferential comparison, or a confidence interval.

Serious adverse events and other adverse events are listed separately, so the entries should not be merged into one category. The safety denominators are the counts recorded as at risk for each group. They should be read as safety information, not as the number with an observed primary viral-status outcome. No serious-event terms are listed in the registry record.

12. What the Result Does, and Does Not, Mean

The registry record establishes that a randomized, triple-masked, parallel-group study compared ciprofloxacin with placebo in adults described as having HIV-associated salivary gland disease. The primary outcome was defined as BK virus positive or negative in oral fluid at Week 4, assessed by real-time PCR. This identifies the planned comparison and the biological measure the study intended to examine.

The record does not report group-specific Week 4 viral-status results, an estimate of the treatment-group contrast, or an uncertainty interval. It therefore does not show the magnitude, direction, or precision of a primary-outcome difference. The study summary’s expectation that participants would have elevated viral loads and benefit from ciprofloxacin is not an observed result. The registry record also does not report viral-load values or results for the secondary outcomes of salivary flow and dry-mouth reports.

The safety entries document zero serious adverse events in either group, one other adverse event in the ciprofloxacin group, zero other adverse events in the placebo group, and zero deaths in both groups. These counts describe the registered entries; they do not provide a precise comparison of safety or establish that no unrecorded events occurred.

In general, a study’s design and endpoint definition do not determine its result. Statistical interpretation requires observed outcomes, a comparison method, and an assessment of uncertainty. Without those elements, the registry record cannot support a conclusion about whether the groups differed on BK viral status, salivary function, or dry-mouth reports. Nor does it establish the broader relationship between BK virus and HIV-associated salivary gland disease that the study sought to examine.

The appropriate reading is therefore bounded: the record describes the question, design, and certain safety counts, while leaving the primary and secondary efficacy findings unreported. No claim about treatment benefit or lack of benefit follows from the absence of those results.

13. Why This Trial Matters Statistically

This trial raises a useful statistical question about how a biological endpoint is connected to a broader clinical research question. BK viral status in oral fluid is a direct assay-based measure, while salivary flow and dry-mouth reports describe other aspects of salivary gland function and participant experience. Keeping these outcomes distinct matters: evidence about one measure would not automatically establish a result for the others.

The randomized, parallel-group design offers a framework for comparing assigned treatments. Masking is also recorded, which is relevant because outcome assessment and participant reporting can be affected by knowledge of assignment. Yet design labels alone cannot answer whether a difference was observed. The primary outcome counts, group comparison, and uncertainty are essential for interpreting the trial’s central question, and these are not reported in the registry record.

The entry also illustrates why withdrawals and analysis populations should be reported. Two participants withdrew before the Week 4 primary assessment, but the registry does not explain how those withdrawals were handled. In general, transparent reporting of missing outcomes lets readers judge whether an analysis depends on assumptions that may influence its findings.

Finally, the registry distinguishes serious adverse events from other adverse events and records deaths separately. That structure supports a more careful descriptive reading than a single undifferentiated event count would. The small enrollment and the lack of outcome analyses mean that the reported safety entries are limited descriptions, not precise comparative estimates.

Statistically, the main lesson is the difference between a well-defined question and an answer supported by posted data. The record makes the intended endpoint and design identifiable, but without results and analytic details it does not permit a complete evaluation of the treatment comparison.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The most consequential limitation for interpretation is that the registry record does not report the primary endpoint results by treatment group. Although the endpoint is defined as positive or negative BK viral status in saliva at Week 4, there are no reported group counts, effect estimate, confidence interval, or test result. The study’s primary statistical finding therefore cannot be assessed from the record.

The record reports that two participants withdrew before Week 4, but does not describe the reason for withdrawal, whether their outcome data were unavailable, or how those participants were handled in an analysis. The analysis population and missing-data approach are not reported. These omissions prevent assessment of whether the primary comparison included all randomized participants or relied on a subset with available outcomes.

The registry lists secondary outcomes for salivary flow and dry-mouth reports at Week 4 and Week 12, but does not provide their results or a plan for interpreting multiple outcomes. It also does not report a detailed statistical analysis plan, sample-size justification, randomization procedures, or the specific roles included in triple masking. These details are not reported in the registry record.

The safety information is limited to group-level counts and denominators. It does not include a comparative analysis or an uncertainty estimate, and the description of the other adverse event is not reported. Enrollment was 17, so the record reflects a small study; in general, limited enrollment can constrain the precision of estimates. Because the primary efficacy results are absent, however, no precision estimate for that endpoint can be evaluated at all.

These limitations concern what can be concluded from the registry record. They do not establish that an analysis was not conducted outside the record; they mean that such an analysis and its results are not reported there.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: BK Virus in Salivary Gland Disease: Treating the Potential Etiologic Agent — NCT02068846.
• Registry record last updated 2019-07-11; status last verified 2019-06.
• Results first posted 2019-07-11.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

NCT02068846 is a completed Phase 3 randomized, triple-masked, parallel-group study sponsored by the University of North Carolina, Chapel Hill. It enrolled 17 participants and compared ciprofloxacin with placebo, each taken twice daily for 28 days.

The primary endpoint was BK viral status in saliva at Week 4, classified as positive or negative by real-time PCR. The primary-outcome description notes that two participants withdrew before Week 4. The registry record does not report group-specific primary results, an effect estimate, or an analysis. Listed secondary outcomes concern unstimulated salivary flow and dry-mouth reports at Week 4 and Week 12; their results are not reported.

Safety entries report zero serious adverse events in each group, one other adverse event in the ciprofloxacin group, zero in the placebo group, and zero deaths in both groups. These counts are descriptive and do not provide a precise comparative safety estimate.